1. Field of Invention
This invention relates to a method for molding axially hollow grommets as well as a device and mold for use therein.
2. Description of Prior Art
In the automotive industry, a grommet is used to seal a hole in a panel through which a wire harness has passed. Generally it is molded from an elastomeric material and the wire harness is passed through the grommet prior to insertion. Since the grommet is made of an elastomer, it is able to deform and fill the hole through which the wire harness passes and provide both soundproofing and waterproofing. Typically, the panel is a firewall and thus the soundproofing and waterproofing aspect is between the engine compartment and the passenger compartment.
Conventionally, grommets have been molded in a funnel design, wherein the large end has a stopping flange which interacted with the panel so as to fill the hole. The small end fits tightly around the bundle of wires in the wire harness so as to form a secure seal.
An improved design for a grommet has been suggested in Japanese Application Number 61-112732, filed Jul. 24, 1986. In this Application, the grommet, as removed from the mold, is shown in FIG. 1. Grommet 15 comprises hollow 30, body 24, long tube funnel section 31 and short tube funnel section 32. Funnel sections 31 and 32 have long tube portions and short tube portions which have been marked 33 and 34, respectively. Annular depression 35 is molded into body 24 of grommet 15. Also, reinforcement 38 is molded into end 17 of long tube portion 33.
FIGS. 2 and 3 illustrate the use of grommet 15 with wire harness W/H to fill a hole in panel P. As shown therein, the user of grommet 15 must invert long tube funnel section 31 into short tube funnel section 32 so that long tube portion 33 doubles within short tube portion 34, thus forming double walled portion 36. Wire harness W/H is then inserted through grommet 15 and tape 39 is secured around the end of double walled portion 36. Because of cavities 37, body 24 is able to deform as shown in FIGS. 2 and 3, so that grommet 15 can be easily inserted into the hole in panel P. The arrows in FIG. 2 illustrate the flexing action of the elastomeric material used to mold grommet 15. It is preferred that sealant 40 be injected around the wire harness so as to increase the waterproofing and soundproofing ability of the grommet.
one of the problems with grommet 15 is that the operator, when mounting the grommet on the wire harness, has a difficult time inverting long tube funnel section 31 into short tube funnel section 32.
It is well known to mold thermoplastic resin or rubber materials about a mandrel within the cavity of a split mold into a hollow article having an axial opening therethrough. However, there is no prior art device that could remove the object from the mandrel after molding and, at the same time, insert long tube funnel section 31 into short tube funnel section 32. It is an object of the present Invention to provide apparatus which is capable of being utilized rapidly and reliably.